Carbon nanotubes (CNT) are quasi-one dimensional structures which are obtained by rolling up graphene sheets into cylinders. There are single wall carbon nanotubes, consisting of one sheet, and multi-wall carbon nanotubes, consisting of two or more concentric cylindrical sheets. The particular way of graphene rolling is characterized by a chirality index (n,m), which determines if the rolled graphene is metallic or semiconducting. In addition, CNT can have diameters in the range of 0.5-1.5 nm and lengths up to several micrometers.
CNTs have received much attention due to their potential applications as integrated nanoscale elements in various devices. Low-friction, low-wear multi-wall CNT bearings have been demonstrated. Prior work in the art has shown that if an inner tube from a double wall nanotube is extruded with respect to the stationary outer tube, the inner tube can easily slide or rotate due to the intertube van der Waals (vdW) interaction. Such devices have been reported to have very low friction—at least two orders of magnitude smaller than the vdW forces.
Scanning probe microscopes, such as the Atomic Force Microscope (AFM), are examples of scanning probe imaging and sensing devices. These devices are useful for surface profiling. A non-contact AFM measures the microscopic surface profile of a near-planar target using a nanometer-scale probe that is mounted at the end of a tiny cantilever. Deflection of the cantilever, as the probe is raster-scanned across the surface of the target, is optically measured. The measurements are used to establish a profile of the target surface. However, the resolution of the AFM is limited by the probe tip radius, which is on the order of a few tens of nanometers.
Accordingly, what is needed in the art is a non-contact surface profiling device that provides an improved resolution over the AFM systems currently known in the art.